Cream butter and sugar. Add the egg and vanilla. In a medium bowl, sift together the dry ingredients and mix well. Add to the wet ingredients and mix just until barely combined. Using your hands, use a kneading motion inside the bowl so that the dough starts to come together. Flour your hands if the dough is sticking to you. Divide into two parts, flatten into disks, and wrap in plastic wrap. Refrigerate for at least 2 hours.

Preheat oven to 350 F. Take out one of the disks and roll out to 1/4" thick on a floured surface. Using a small, scalloped cookie cutter, cut out cookies (I used a miniature Wilton Christmas tree cookie cutter to cut out the middle of half the cookies) and bake for 8 minutes, until edges are just slightly golden brown.

Combine ingredients in a stand mixer with the paddle attachment until soft and smooth. Transfer to a piping bag with plain tip about 1/2" in diameter (or, if you don't have one, just use a zip-loc bag and cut a corner off like I did). Ice in a side to side motion to get the pattern--I loved the way it made my trees look! Sandwich cream in between two cookies.

These cookies are very rich, so the smaller you cut them out, the better. Of course, my Handsome Man didn't complain about the large ones I made!